WO2005102068A1

WO2005102068A1 - A process and a process unit for separating at least proteins from an organic raw material

Info

Publication number: WO2005102068A1
Application number: PCT/DK2004/000287
Authority: WO
Inventors: Poul Hjulmand; Steen Buhl Larsen; Kurt Tobler
Original assignee: Landia A/S
Priority date: 2004-04-26
Filing date: 2004-04-26
Publication date: 2005-11-03

Abstract

The present invention describes a process for the separation of at least proteins from an organic raw material, comprising the steps of: a) arranging the raw material in a reactor container in a process unit, at the bottom of which reactor container, a cutter or shredder is arranged immediately adjacent a pump unit, where said pump unit may be arranged to recirculate/stir and thereby mix the raw material arranged in the reactor container or alternatively pump out the material from the reactor container; b) optionally adding water to the raw material; c) activating the pump means for mixing the raw material and for drawing the raw material through the cutter or shredder, until a substantially homogeneous liquid mass is present in the reactor container, and depending on the organic raw material a substantially granular fraction; d) adding an additive, such as for example a preservative, an enzyme or similar substance; e) continue the mixing process until the additives have had sufficient reaction time; f) switching the pump means from its mixing mode to its pumping out mode whereby the reactor container is emptied; g) depending on the additive, the liquid mass and the granular fraction when preservatives are added are transferred to storage vessels, and when enzymes are used as additives the liquid mass and the granular fraction are transferred to a decanter for separation of proteins, oils and sediments; h) the process unit is ready for the following batch, and may optionally be cleaned before the following cycle.

Description

A PROCESS AND A PROCESS UNIT FOR SEPARATING AT LEAST PROTEINS FROM AN ORGANIC RAW MATERIAL

Background of the invention The present invention relates to a process as well as a process unit used for the separation of at least proteins from an organic raw material. 5 In food processing and especially where organic raw materials such as cattle, pigs, chicken, fish and the like are involved a substantial amount of organic waste is produced, i.e. bones, fat, etc. In addition to the prime cuts, filets, etc., a certain amount of offal is left-over. Depending on the origin of the offal, i.e. whether it stems from cat- 10 tie, pigs, chickens or fish, they contain various amounts of substances which if refined and reclaimed, may be used as natural additives to further processing or different food processing steps. It may therefore be advantageous to regain these materials and turn them into valuable additives instead of having to dispose of such waste with the expenses involved. 15 When the offal stems from pigs and especially cattle, the bone part of this offal makes it difficult to reuse as the bones are relatively hard and, therefore, makes economic use of the organic matter between the bones difficult to justify. For other types of offal such as for example fish and especially salmon and trout, the oil content in the offal is 20 an obstruction to regaining proteins, vitamins and other desirable substance in that the oil fraction is not separated from the other useful substances, but it is an integrated part of the offal matrix. For chicken offal, the remaining organic fraction is limited and therefore from an economic point of view, regaining of the desirable substances has not been considered feasible. 25 Consequently, there is a need for a process as well as a process unit which in an economic feasible manner makes it possible to regain the useful substances from what up until now has been considered organic waste, or which through other processes in the art has not yielded enough to find widespread use. 30 The present invention addresses this by providing a process for the separation of at least proteins from an organic raw material, comprising the steps of: a) arranging the raw material in a reactor container in a process unit, at the bottom of which reactor container, a cutter or shredder is arranged immediately adjacent a pump unit, where said pump unit may be arranged to recirculate/stir and thereby mix the raw material arranged in the reactor container or alternatively pump out the material from the reactor container; b) optionally adding water to the raw material; c) activating the pump means for mixing the raw material and for drawing the raw material through the cutter or shredder, until a substantially homogeneous liquid mass is present in the reactor container, and depending on the organic raw mate- rial a substantially granular fraction; d) adding an additive, such as for example a preservative, an enzyme or similar substance; e) continue the mixing process until the additives have had sufficient reaction time; f) switching the pump means from its mixing mode to its pumping out mode whereby the reactor container is emptied g) depending on the additive, the liquid mass and the granular fraction when preservatives are added are transferred to storage vessels, and when enzymes are used as additives the liquid mass and the granular fraction are transferred to a decanter for separation of proteins, oils and sediments h) the process unit is ready for the following batch, and may optionally be cleaned before the following cycle.

The inventive process is the batch process meaning that a predetermined amount of material is treated where after a following amount of material is introduced into the process. This provides the process with a high degree of flexibility in that different materials needing different additives or having different optimum viscosities may be treated within the same process and also the same process unit, and furthermore, that only a limited amount of cleaning is necessary in order to switch from treating one type of organic raw material to treating a different kind of organic raw material.

Furthermore, the provision of cutters or shredders for example in the form of knives arranged inside a reactor container will divide the introduced organic raw material/offal into rather small particles such that it is possible to effectively treat all the organic matter present in the amount of organic raw material introduced into the reactor container.

Where enzymes are added for the separation of proteins or preservatives for providing a organic mass which may be preserved for a certain period of time in order to transport it or store it for further treatment, in a following process step, a thorough mixing of the additives with the introduced organic material is ensured such that a homogeneous mass is created whereby the effectiveness of the additives is maximised.

As the process which for offal usually lasts about sixty minutes is over, the enzymes have had sufficient time in order to synthesize the proteins and vitamins, the pump means which has a dual function is able to empty the reactor container as the solid parts of the organic material when this is offal, the bones, have been shredded/cut to a size which makes it possible to without problems pump them out of the reactor con- tainer together with the liquid mass. From the process unit, in cases where offal is being treated, the liquid mass is usually transferred to a decanter where due to the decanting process, the oil, proteins etc. are separated from the waste such as the bone fractions.

Under certain circumstances depending on the introduced organic raw material, it may be advantageous to add water to the raw material. It should however be noted that water is undesirable in the process as it needs to be separated from the liquid mass at a later stage which may involve an extra costly process step. If the viscosity of the liquid mass after having been made homogenous by the recirculation stirring process as well as being passed through the cutter and shredder, the addition of water to the liquid mass should be kept at a minimum and preferably avoided all together.

As the batch process is over, the liquid mass is transferred to either a storage vessel when the batch process has involved preservatives or to a decanter when enzymes have been used. In the storage vessel depending on the materials, it will be possible to store and keep the liquid mass for example until further processing or for a specified time before using the liquid mass as feed stuffs in the animal industry. Where enzymes have been used, the decanting process will separate the liquid mass into a protein, oil and sediment fraction as well as water fraction. Tests with the batch process as described above have indicated that the protein yield and the purity of proteins obtained by the processes described above by using enzymes for example manufactured by No- vozymes of Denmark have a superior quality and yield compared to other processes for regenerating proteins.

In a further advantageous embodiment, the organic material is waste from food stuff manufacturing, such as fish processing plants, slaughterhouses, meat production plants, or any other foodstuff industry, restaurants, fast-food production or retail out- lets. As all these materials comprise organic material which in one way or another is constituted by proteins, vitamins, oils/fats, they are all useful ingredients in a process as described above and may advantageously be used in such a batch process.

In a still further advantageous embodiment of the invention, the organic raw material is waste water, waste from animal production or materials used in the generation of biogas or other bio fuels. This group of materials comprises ingredients which require special treatment especially with respect to possible pollutants and the like.

In a further advantageous embodiment, it has been found that it, the raw material, de- rives from slaughterhouses, fish processing plants or meat production plants, water is added up to an amount of water corresponding to the weight of the raw material. As mentioned above, it is advantageous to add as little water as possible in that the water is a non-desirable ingredient that at a later stage for example in the decantation process needs to be removed again. Therefore, when possible, as little water as possible should be added. However, in order to be able to thoroughly mix the ingredients, i.e. the meat fractions with the bone fractions as well as any other waste material from animal production or fish processing plants, it has been found that adding a certain amount of water improves the pumpability of the mass as well as the distribution of the active ingredients whether it be enzymes or preservatives throughout the entire liquid mass.

In a still further advantageous embodiment, it has been found that in order to achieve a higher yield with a shorter process time, the process should be modified such that between process steps c) and d) the temperature in the reactor container is brought to approximately 55 deg. Celsius. Especially, when enzymes are added to the liquid mass inside the reactor container naturally depending on the type of enzymes, but for most of the enzymes tested with the process unit and process as described above a good economic balance between energy consumption and process time was found to be reached when increasing the temperature in the reactor container to approximately 55 degrees Celsius as this is the point where the enzymes are most active.

The invention is also directed to a process unit for carrying out the process according to any of the steps mentioned above. The process unit is particular in that the unit comprises a reactor container defining a volume, said container having downwardly sloping bottom, and further an openable and/or removable lid structure, that a knife or shredder means is arranged adjacent a drain arranged in the bottom, and that the drain connects the container to a pump means, where said pump by means of a valve is optionally connected to recirculating means and/or pipe means.

The particular inventive feature of arranging a knife or shredder means immediately adjacent a drain where the pump has two outlets provides a number of advantages for the process unit according to the invention. Firstly, as the material to be treated is introduced into the process unit, the knife or shredder means divides the material up into finer pieces which the pump means will be able to pump together with any liquid either especially added or contained in the waste material. The shredder/knife means thereby makes it possible to transport the waste material including the divided bone parts through the drain to the pump means. The pump means is equipped with two outlets such that it may pump the liquid containing the shredded bone materials back into the reactor container or after the treatment cycle according to the process described above has finished pumping the material either to further treatment or to a storage vessel. By pumping the material back into the reactor container, the pump recirculates and thereby stirs the material in the reactor container such that a thorough mix will take place in the waste material inside the reactor container. Furthermore, as the material repeatedly passes the knife or shredder means arranged immediately adjacent the drain leading to the pump means, the hard particles such as bone and the like will repeatedly be worked over by the knife or shredder means whereby ever finer particles will be present in the liquid mass. The downwardly sloping bottom assures that heavier particles such as bones and the like, due to the influence of gravity, will also be moved towards the shredder/knife mechanism, and thereby successively will be reduced to smaller particles due to the circulation of the liquid mass in the container.

In a further advantageous embodiment the container has substantially vertical sides and a conically shaped bottom.

By further shaping the reactor container such that it has substantially vertical sides and a conically shaped downwardly facing bottom, the harder particles which are not able to float on the surface will be forced both due to gravitational forces and also due to the sucking force of the pump means through the knife and/or shredder means such that all material present inside the reactor container will be worked through both the shredder/knife means and the pump means for a thorough mixing.

As the batch process as described above has finished, i.e. a thorough mixing and addition of the suitable additives have been concluded, the valve arranged in connection with the pump means is redirected such that instead of recirculating the material inside the reactor container, the liquid mass is pumped out of the process unit after which a further batch of material may be introduced into the reactor container.

In a further advantageous embodiment of the process unit, a thermal insulation jacket is provided around at least the reactor container, and that means are provided for heating and/or cooling, and means for controlling the temperature inside the container, where said source of heating may be electrical, gas in particular biogas, oil or any other suitable source.

By providing a thermal insulation jacket in combination with means for either heating the contents inside the reactor container or cooling the same, it is possible to com- pletely control the process inside the reactor container and thereby optimise the process such that a higher yield and/or less energy consumption and other advantages may be derived at. Furthermore, in particular when it is desirable to treat raw material as described above where the raw material is waste water or waster from animal production or materials used in the generation of bio-gas or other bio-fuels, it may be desirable to be able to reliably achieve the temperature necessary in order to pasteurize the material.

Furthermore, when treating a number of waste materials, it is required by law that the materials through their process is brought up to a certain temperature in order to avoid spreading a bacteria and the like. This is particularly important where the process is a preserving process such that the materials after treatment will be used for further proc- essing for example as an ingredient in food stuffs or animal feed. Also in other processes for example when waste water is treated by adding enzymes, it is possible to regain active coal which may be used in connection with water purification plants. In this case, it is also desirable to create a pure material i.e. a material which is free from other cultures of bacteria such that a pure active coal may be regained.

The source of heating may be any suitable source, but it was found that an electrical heating core outside the reactor container which typically will be made from stainless steel gives an easy controllable source of heating energy. For installations working on substances used in the process of biogas it may be advantageous to use biogas as a source of energy, and due to the construction material of the reactor chamber which will usually be steel and in particular stainless steel, a relatively good heat distribution is assured even when it derives from burning biogas, oil or other bio-fuels. In this connection, oil may be any type of oil such as oil from fossil deposits or biological oils for example fat from fish or meat production.

In a further advantageous embodiment of the process unit, agitation means are provided inside the container, and that said agitation means may be one or more vanes or wings arranged on a substantial vertical axle, that the agitation means optionally may be coupled to the pump means such that the rotational speed of the pump and the axle are substantially coupled, and that optionally a front edge of the one or more vanes or wings may be sharpened. The agitation means may advantageously be fitted especially to larger reactor containers in that a thorough mixing of the materials placed inside the container may be assured. By using only the pump means in order to agitate and mix the ingredients placed inside the reactor container depending on circumstances and the size of the reactor container, certain flow patterns may arise such that only parts of the raw materials placed in the reactor container become thoroughly cut and shredded and mixed. Therefore, by providing agitation means for example in the shape of vanes or wings and where a front forward edge of the wings is sharpened, a thorough mixing of the entire volume inside the reactor container may be achieved. In this connection, for- ward direction shall be construed as meaning the direction in which the wings travel due to the rotation of the axle.

The axle may for example via a gearbox be coupled to the pump means such that the speed of the pump is reflected in the rotational speed of the agitation means. A gear box may be provided such that any desired speed relationship between the pump and the agitation means may be selected.

Both for the optimization of the process as described above and for the process unit as described herewith, it may be advantageous to be able to control the speed of the pump. If the pump moves too fast, bubbles or other hydraulically undesirable phenomenon may occur either inside the pump or in the outlet from the pump leading back to the recirculation means inside the reactor container. This may cause that the additives become inactive due to the mixing of oxygen into the mask or that the energy consumption by the pump depending on the size of the particles inside the liquid mass is not optimised such that a substantial amount of energy is wasted in the pump which again leads to unnecessary wear in the mechanical parts of the process unit. Tests with especially waste from fish processing plants and in particular with salmon have indicated that various pump speeds are desirable during a batch cycle where also the temperature inside the reactor container should be varied but mainly kept at 55 degrees Celsius.

In order to widen the flexibility of the present process unit, means are provided such that the temperature is controllable between 0 degrees and 100 degrees Celsius. By providing control means not only for controlling the pump speed, speed of the agitation means, but also controlling the temperature, it becomes possible to create a versatile process unit which is able to operate under any temperatures such that the optimal temperature may be chosen or derived at depending on the case in point, namely what kind of raw materials that have been added, what kind of additives that are intended to be added, and what kind of result is desirable to achieve with the process.

In order to further optimize this process, the process unit is provided with an automatic pre-programmable and optionally remotely controllable dosing unit which is in communication with the interior of the container for adding water and/or enzymes and/or preservatives, and that further process control and monitoring equipment is provided in the unit, optionally connected by wire or wireless means to a remote control installation.

When the process unit is used in a standardised manner, i.e. such that all batches contain the same type of raw material for example fish waste, the entire process may be automated by providing the process unit with appropriate means such as means for dosing water, enzymes, preservatives or other additives, and at the same time, the control unit may be equipped with monitoring equipment such as for example thermocou- pies, flow meters for determining the viscosity of the liquid mass, video camera means for visually inspection of the inside of the container, electrodes for determining the conductivity of the mass inside the reactor or any other monitoring means which are per se known in the art. In order to be able to control the process from a central location, the dosing unit and monitoring equipment may be connected to a remote control installation by wire or wireless means. For some installations, it might be desirable to have more than one process unit and, therefore, by collecting all the data to one centrally arranged control installation, it will be possible for the personnel operating the machinery to control more than one process unit for example via a personal computer hooked up in a wire or wireless environment.

Description of the drawing

One specific embodiment of the invention will now be described with reference to the accompanying drawing wherein fig. 1 illustrates a schematic process unit according to the invention.

In fig. 1- a process unit according to the invention is illustrated. The process unit 1 comprises a reactor container 2. The reactor container may be manufactured from any suitable material but especially stainless steel is preferred in that it is resistant to most chemicals and at the same time, it is possible to clean and rinse stainless steel to the high hygienic requirements which are prevailing within the food production industry. Alternatively, the reactor may be manufactured from glass fibre reinforced resins, plastics, especially reinforced plastics or metals such as aluminium and steel.

The reactor container comprises in this particular embodiment substantially vertical wall sections 3 which are connected to a cone shaped bottom section 4. At this bottom-most part of the cone section 4, a drain 5 is arranged which is connected to a pump 6.

Either integral with the pump 6 or immediately adjacent the pump inside the drain 5, a set of knives and/or a shredding mechanism 7 is arranged. Pumps comprising a knife arrangement or a shredding mechanism are well-known in the art, and suitable pumps may be obtained from Landia A/S in Denmark.

The pump has two outlets 8,9. Either integral with the pump or arranged in each outlet 8,9, valve mechanisms 10,11 are arranged. In the illustrated embodiment in fig 1, two separate valves are provided 10,11 which are controlled by a control box 12 by electrical means illustrated by the wires 13. In this manner, it is assured that by manipulating the control box 12, the valves 10,11 may be operated to either close or open such that material placed in the reactor container 2 may, by means of the pump, be pumped out of the container and either to the outlet 9 or to the recirculation means 8. If the valve 10 is open, and the valve 11 is closed, the mass placed in the reactor container will be pumped through the outlet means 8 which serves as recirculation means. The mass is injected into the container 3 by the outlet 8 which is connected to the side of for example the cone-shaped bottom 4. This creates a mixing and stirring action in the liquid mass placed in the container 2 such that a thorough mixing of the ingredients inside the reactor container 2 may be optimised. In addition to the stirring/mixing action created by the recirculation of the liquid mass in the container by means of the pump and the outlet 8, a substantially vertical axle 14 may be arranged inside the reactor container 2. On the axle, wings or vanes 15 may further be provided such that a thorough mixing of the liquid mass placed inside the reactor container is facilitated. The axle 14 may be coupled to the pump means 6 such that the rotational speed of the axle 14 and thereby the wings 15 is coupled to the speed of the pump 6. The coupling may either be direct or be via a gear box. Alternatively, the vertical axle may comprise its own drive means which has not been depicted in fig. 1.

The wings or vanes are designed such that optimum mixing is achieved with a minimum of energy use. Additionally the wings or vanes may be provided with sharp front edges such that a cutting action may be achieved during the mixing, i.e. rotation of the axle 14.

The control box 12 may be provided with further functions such as for example temperature measurement devices for example in the form of thermocouples, timers, a programmable computer unit as well as a storage and/or means for transmission of information/data from the control box 12 to a remote control base.

In order to be able to optimize the conditions inside the reactor container 2, the walls 3,4 of the container 2 may be provided with an insulation jacket 15 as illustrated on the left-hand portion of the reactor container depicted in fig. 1. Although only insulation on the left-hand side of the fig is illustrated, it is evident that in order to achieve the desired effects, the entire container or substantial parts of the container must be covered by insulation means 15.

In addition to the insulation means 15, heating means 16 in this embodiment depicted as heating pipes placed immediately adjacent the wall 3,4 of the container as illus- trated. The heating means may be any type such as for example a gas heater distributing the heat in a pipe system 17. Alternatively, the pipe system will be used for cooling the container 2 in order to control the reactions inside the reactor container 2. Generally, the means for heating and/or cooling may be any suitable means which will be able to maintain a temperature in the desired intervals for the desired reaction time.

In addition to the reactor container 2 defined by the walls 3,4, a lid 18 is provided. The lid may be pivotally mounted by means 19 such that access may be gained to the interior of the reactor container. Furthermore, the lid 18 may also be provided with a thermal insulation jacket as the rest of the container 2. The dash-lines indicate that the lid is openable but in alternative embodiments, the lid may also be removable in order to place the material to be treated inside the reactor container 2.

Additionally, a dosing unit 19 may be provided in the apparatus 1. The dosing unit 19 may be controlled either by a control box 12 or by remote control means such that depending on the materials to be treated inside the process unit 1, appropriate additives or water may be added to the reactor container 2. The dosing unit 19 may be suit- able to add additives such as enzymes, preservatives or other reactants as well as water.

As the process unit 1 is suitable for a number of different processes such as for example separation processes in connection with separating proteins, oils etc. from offal where it is desirable to add enzymes which will further improve this process or other processes where it is desirable to preserve the liquid mass being produced by the system, preservatives should be added by the dosing unit 19. The dosing unit 19 must be multifunctional or must be replaceable by other suitable dosing units in order to be able to administer the suitable substances in suitable amounts. Furthermore, the dosing unit 19 may either be connected to a control box 12 as explained above or may be controllable by wires or wireless means from a remote position for example a centrally located control base.

In use, the offal or other organic raw material is placed inside the reactor container 2 in an appropriate amount corresponding to the size of the container. Thereafter, water is added if necessary, and the pump means 6 as well as the axle 14 is activated such that circulation of the raw material placed inside the reactor container is effected. During the circulation, the valve 10 is open, and the valve 11 is closed such that the raw material will be circulated through the knife arrangement 7 whereby a cutting of larger items such as bones and the like will occur through the pump means 6. The liquid mass will pass the valve means 10 and by means of the recirculation outlet 8 be injected back into the mass of raw material placed inside the reactor container 2. Due to the knives 7 arranged in the drain 5, the materials placed inside the reactor container will be divided and the more, i.e. the longer, the recirculation of material lasts, the finer the division of the particles inside the liquid mass placed in the container will be.

If appropriate, the heating means 16 or the cooling means 17 will be activated in order to reach the optimum process temperature. For example when offal is treated where enzymes are added by a dosing unit, the optimum temperature has been found to be approximately 55 degrees Celsius. At this temperature, the pump speed may be varied such that the pump means 6 creates a recirculation in the raw material placed in the container 2 for optimum distribution of the enzymes throughout the raw material placed inside the container. Furthermore, the vanes and/or wings 15 will further help in creating a homogenous mass. The process time for the processing of offal using enzymes in order to separate oils, proteins etc. is typically approximately 1 hour. After the process time or immediately before the process time is over, the raw material/liquid mass inside the reactor container 2 may advantageously be heated up to ap- proximately 90 degrees Celsius for a very short period of time in order to stop the process and at the same time destroy any undesirable bacteria culture being present in the liquid mass.

For other purposes, other temperatures and process times may be appropriate, as well as the process described above may also be carried out at lower temperatures whereby the process time is prolonged.

At the end of the process, the valve 10 is closed, and at the same time, the valve 11 is open such that the pump will pump the material from inside the container 2 to further processing by pumping it out through the outlet 9. When the container 2 is empty, the valve 11 is closed and a cleaning liquid may be placed inside the container, the pump means activated and the valve 10 open such that recirculation and thereby cleaning of all interior surfaces is achieved. After the cleaning cycle, the cleaning liquid may by means of closing the valve 10 and opening the valve 11 be drained from the reactor and the process unit is thereby ready to receive a new batch of material to be treated.

Claims

1. Process for the separation of at least proteins from an organic raw material, comprising the steps of: a) arranging the raw material in a reactor container in a process unit, at the bottom of which reactor container, a cutter or shredder is arranged immediately adjacent a pump unit, where said pump unit may be arranged to recirculate/stir and thereby mix the raw material arranged in the reactor container or alternatively pump out the material from the reactor container; b) optionally adding water to the raw material; c) activating the pump means for mixing the raw material and for drawing the raw material through the cutter or shredder, until a substantially homogeneous liquid mass is present in the reactor container, and depending on the organic raw material a substantially granular fraction; d) adding an additive, such as for example a preservative, an enzyme or similar substance; e) continue the mixing process until the additives have had sufficient reaction time; f) switching the pump means from its mixing mode to its pumping out mode whereby the reactor container is emptied g) depending on the additive, the liquid mass and the granular fraction when preservatives are added are transferred to storage vessels, and when enzymes are used as additives the liquid mass and the granular fraction are transferred to a decanter for separation of proteins, oils and sediments h) the process unit is ready for the following batch, and may optionally be cleaned before the following cycle.

2. Process according to claim 1 c h a r a c t e r i s e d in that the organic raw material is waste from food stuff manufacturing, such as fish processing plants, slaughterhouses, meat production plants, or any other foodstuff industry, restaurants, fast-food produc- tion or retail outlets.

3. Process according to claim 1 characterised in that the organic raw material is waste water, waste from animal production or materials used in the generation of biogas or other bio fuels.

4. Process according to claim 1 or2characterisedin that when the raw material derives from slaughterhouses, fish processing plants or meat production plants, water is added up to an amount of water corresponding to the weight of the raw material.

5. Process according to claim l,2or4characterisedin that between process steps c) and d) the temperature in the reactor container is brought to approximately 55 deg. Celsius.

6. Process unit for carrying out the process according to any of claims lto5charac t e r i s e d in that the unit comprises a reactor container defining a volume, said con- tainer having substantially vertical sides and a downwardly sloping bottom, and further an openable and/or removable lid structure, that a knife or shredder means is arranged adjacent a drain arranged in the bottom, and that the drain connects the container to a pump means, where said pump by means of a valve is connected to recirculating means or pipe means.

7. Process unit according to claim όcharacterisedin that the reactor container has substantially vertically sides and a conically shaped downwardly facing bottom.

8. Process unit according to claim 6or7characterisedin that a thermal insula- tion jacket is provided around at least the reactor container, and that means are provided for heating and/or cooling, and means for controlling the temperature inside the container, where said source of heating may be electrical, gas in particular biogas, oil or any other suitable source.

9. Process unit according to claim 6, 7or8characterisedin that agitation means are provided inside the container, and that said agitation means may be one or more vanes or wings arranged on a substantial vertical axle, that the agitation means optionally may be coupled to the pump means such that the rotational speed of the pump and the axle are substantially coupled, and that optionally a front edge of the one or more vanes or wings may be sharpened.

10. Process unit according to any of claims 6to9characterisedin that the tem- perature is controllable between 0 deg. and 100 deg. Celsius.

11. Process unit according to any of claims 6 to lOcharacterisedin that an automatic pre-programmable and optionally remotely controllable dosing unit is in communication with the interior of the container for adding water and/or enzymes and/or preservatives, and that further process control and monitoring equipment is provided in the unit, optionally connected by wire or wireless means to a remote control installation.